The present invention relates to the method of manufacturing single crystal material valuable for a superconductive element, a semi-conductive element, or an optical electronics element which are widely utilized in the electronics industry.
BaPb.sub.1-x Bi.sub.x O.sub.3 (barium lead bismuth oxide) constructed of the Perovskite structure, shows superconductivity at a range of 0.05.ltoreq.x.ltoreq.0.30, semimetallic characteristic at a range of x&lt;0.05, and semiconductivity at a range of 0.30&lt;x. Super-conductive transition temperature Tc shows 13 K. at the highest degree when x=approximately 0.25, and this degree is the highest degree in the oxide super-conductor that does not include transition metal elements, and is an extraordinary high degree in oxide super-conductors. This compound is given attention because of its super-conductivity and its composition dependency on this super-conductivity. Further, the compounds of this series include semimetallic material and its carrier density n is small, and the electron condition density N (o) at the Fermi surface is extraordinarily small as a super-conductor. Therefore, this material has a resistance rate that shows several values higher than ordinary metal super-conductors at a temperature a little higher than Tc. This is, the characteristic that is expected as an element for super-conductive switches. When this material is crystallized as a single crystal, it can get more stability, and when optically transparent crystal is obtained at the infrared rays region, it can be expected as a material for optical electronics elements at a super-low temperature.
Conventionally, growing up BaPb.sub.1-x Bi.sub.x O.sub.3 single crystal is carried out by the crystallization utilizing a flux. According to one method, KCl can be utilized as the main component of the flux. KCl flux is favorable as a flux to dissolve BaPb.sub.1-x Bi.sub.x O.sub.3, but to dissolve KCl and to melt KCl in BaPb.sub.1-x Bi.sub.x O.sub.3, a high temperature of about 1000.degree. C. is necessary, and thus potassium ion remains inside BaPb.sub.1-x Bi.sub.x O.sub.3 single crystal, and thus the impurity density becomes large. Also, as the material grows at a temperature higher than the transition point of BaPb.sub.1-x Bi.sub.x O.sub.3, the point existing in a range from of 500.degree. C. to 600.degree. C., crystal phase transition occurs during cooling down, and therefore, a strain largely occurs within the crystal.
There is another method utilizing PbO.sub.2 -Bi.sub.2 O.sub.3 -BaPbO.sub.3 solution which is a non-stoichiometric compound solution. In this case, there is an advantage that the enclosure of the impurity material will lessen greatly, but, when crystallizing BaPb.sub.1-x Bi.sub.x O.sub.3 from the non-stoichiometric compound, controlling the composition factor x that determines the characteristics of the material, is very difficult. Also, a strain accompanying the phase transition, occurs as stated above.
Technology of the above prior art is disclosed in the following document, Akinori Katsui; Japanese Journal of Applied Physics Vol. 21 No. 9, (1982) Page 553 to 554.
In accordance with the conventional method of manufacturing BaPb.sub.1-x Bi.sub.x O.sub.3 single crystal, the impurity density within the material is large, and also, the change of composition factor x in the material is many. Also the conventional method has large problems, such as the reappearance characteristic of composition x is bad, and the phase transition occurs, and the heat strain remains because of the high temperature process at about 1000.degree. C., and these problems are the major factors that prevent the sharp transition to the super-conductivity of the material.